SCIENTISTS working for a marine conservation organisation have been surprised to find an enormous increase in the amounts and variety of species of fish in the Severn Estuary.
Lymington-based Pisces Conservation, which has been studying the numbers and make up of fish stocks in the Severn for 20 years, has concluded the estuary is becoming cleaner – and warmer.
"We have noticed a fairly big improvement in the area," said Dr Peter Henderson, who has been carrying out the study which is part funded by power station owners British Energy.
The main revelations were that fish and crustacean stocks overall were three times higher than in the 1980s, and numbers of species up from 13 to 16, with this year a huge increase in shrimp numbers, more cod and more allis and twaite shad.
The latter had a very bad time in the 1980s but now appeared to be recovering, largely because of warmer water he thought.
However it was "bad news" for salmonids – salmon and sea-trout – seriously in decline.
"A lot of it is due to a much cleaner river and closure of power stations. However we have also seen the water getting warmer," Dr Henderson told the Review.
He was hoping to obtain more funding for further studies on the effects of global warming on fish stocks.
Dr Henderson said he was upset by the huge numbers of fish killed by power stations which amounted to "hundreds of thousands" annually.
"This is an important nursery area for species like bass. If a fisherman at Lydney say, killed a couple of undersize bass they would be prosecuted. The power station, on the other hand, which kills thousands on a regular basis, gets away Scot free."